Field of the Invention
This disclosure relates to a technology for detecting an amount of developer by detecting a change in electric capacitance.
Description of the Related Art
Many of electrophotographic image forming apparatuses are provided with a remaining-amount-of-toner detecting device configured to notify a user when a developer (hereinafter, referred to as toner) is consumed. Examples of the remaining-amount-of-toner detecting device include a system that detects a change in electrostatic capacitance between a plurality of electrodes arranged in a developing container and detects an amount of toner. The electrodes are generally configured as a so-called electrode plate detecting type in which an electrode plate is arranged at a predetermined distance from a developer bearing member, and electrostatic capacitance between the electrode and the developer bearing member is detected.
In order to improve a remaining-amount-of-toner detection accuracy, a method of using a comparison with a comparison circuit as described in Japanese Patent Laid-Open No. 9-190067 is proposed. In addition, a method of providing a comparison circuit and being added with a stirring cycle as described in Japanese Patent Laid-Open No. 2007-264612 is also proposed.
However, the apparatus configured to detect the remaining amount of toner has a high cost, and hence further cost reduction has been required.